#' Create date input
#'
#' Creates a text input which, when clicked on, brings up a calendar that
#' the user can click on to select dates.
#'
#' The date `format` string specifies how the date will be displayed in
#' the browser. It allows the following values:
#'
#' \itemize{
#'   \item `yy` Year without century (12)
#'   \item `yyyy` Year with century (2012)
#'   \item `mm` Month number, with leading zero (01-12)
#'   \item `m` Month number, without leading zero (1-12)
#'   \item `M` Abbreviated month name
#'   \item `MM` Full month name
#'   \item `dd` Day of month with leading zero
#'   \item `d` Day of month without leading zero
#'   \item `D` Abbreviated weekday name
#'   \item `DD` Full weekday name
#' }
#'
#' @inheritParams textInput
#' @param value The starting date. Either a Date object, or a string in
#'   `yyyy-mm-dd` format. If NULL (the default), will use the current date
#'   in the client's time zone.
#' @param min The minimum allowed date. Either a Date object, or a string in
#'   `yyyy-mm-dd` format.
#' @param max The maximum allowed date. Either a Date object, or a string in
#'   `yyyy-mm-dd` format.
#' @param format The format of the date to display in the browser. Defaults to
#'   `"yyyy-mm-dd"`.
#' @param startview The date range shown when the input object is first clicked.
#'   Can be "month" (the default), "year", or "decade".
#' @param weekstart Which day is the start of the week. Should be an integer
#'   from 0 (Sunday) to 6 (Saturday).
#' @param language The language used for month and day names. Default is "en".
#'   Other valid values include "ar", "az", "bg", "bs", "ca", "cs", "cy", "da",
#'   "de", "el", "en-AU", "en-GB", "eo", "es", "et", "eu", "fa", "fi", "fo",
#'   "fr-CH", "fr", "gl", "he", "hr", "hu", "hy", "id", "is", "it-CH", "it",
#'   "ja", "ka", "kh", "kk", "ko", "kr", "lt", "lv", "me", "mk", "mn", "ms",
#'   "nb", "nl-BE", "nl", "no", "pl", "pt-BR", "pt", "ro", "rs-latin", "rs",
#'   "ru", "sk", "sl", "sq", "sr-latin", "sr", "sv", "sw", "th", "tr", "uk",
#'   "vi", "zh-CN", and "zh-TW".
#' @param autoclose Whether or not to close the datepicker immediately when a
#'   date is selected.
#' @param datesdisabled Which dates should be disabled. Either a Date object,
#' or a string in `yyyy-mm-dd` format.
#' @param daysofweekdisabled Days of the week that should be disabled. Should be
#'   a integer vector with values from 0 (Sunday) to 6 (Saturday).
#'
#' @family input elements
#' @seealso [dateRangeInput()], [updateDateInput()]
#'
#' @examples
#' ## Only run examples in interactive R sessions
#' if (interactive()) {
#'
#' ui <- fluidPage(
#'   dateInput("date1", "Date:", value = "2012-02-29"),
#'
#'   # Default value is the date in client's time zone
#'   dateInput("date2", "Date:"),
#'
#'   # value is always yyyy-mm-dd, even if the display format is different
#'   dateInput("date3", "Date:", value = "2012-02-29", format = "mm/dd/yy"),
#'
#'   # Pass in a Date object
#'   dateInput("date4", "Date:", value = Sys.Date()-10),
#'
#'   # Use different language and different first day of week
#'   dateInput("date5", "Date:",
#'           language = "ru",
#'           weekstart = 1),
#'
#'   # Start with decade view instead of default month view
#'   dateInput("date6", "Date:",
#'             startview = "decade"),
#'
#'   # Disable Mondays and Tuesdays.
#'   dateInput("date7", "Date:", daysofweekdisabled = c(1,2)),
#'
#'   # Disable specific dates.
#'   dateInput("date8", "Date:", value = "2012-02-29",
#'             datesdisabled = c("2012-03-01", "2012-03-02"))
#' )
#'
#' shinyApp(ui, server = function(input, output) { })
#' }
#'
#' @section Server value:
#' A [Date] vector of length 1.
#'
#' @export
dateInput <- function(inputId, label, value = NULL, min = NULL, max = NULL,
  format = "yyyy-mm-dd", startview = "month", weekstart = 0,
  language = "en", width = NULL, autoclose = TRUE,
  datesdisabled = NULL, daysofweekdisabled = NULL) {

  value <- dateYMD(value, "value")
  min <- dateYMD(min, "min")
  max <- dateYMD(max, "max")
  datesdisabled <- dateYMD(datesdisabled, "datesdisabled")

  value <- restoreInput(id = inputId, default = value)

  tags$div(id = inputId,
    class = "shiny-date-input form-group shiny-input-container",
    style = if (!is.null(width)) paste0("width: ", validateCssUnit(width), ";"),

    shinyInputLabel(inputId, label),
    tags$input(type = "text",
               class = "form-control",
               # `aria-labelledby` attribute is required for accessibility to avoid doubled labels (#2951).
               `aria-labelledby` = paste0(inputId, "-label"),
               # title attribute is announced for screen readers for date format.
               title = paste("Date format:", format),
               `data-date-language` = language,
               `data-date-week-start` = weekstart,
               `data-date-format` = format,
               `data-date-start-view` = startview,
               `data-min-date` = min,
               `data-max-date` = max,
               `data-initial-date` = value,
               `data-date-autoclose` = if (autoclose) "true" else "false",
               `data-date-dates-disabled` =
                   # Ensure NULL is not sent as `{}` but as 'null'
                   jsonlite::toJSON(datesdisabled, null = 'null'),
               `data-date-days-of-week-disabled` =
                   jsonlite::toJSON(daysofweekdisabled, null = 'null')
    ),
    datePickerDependency()
  )
}


datePickerVersion <- "1.9.0"

datePickerDependency <- function(theme) {
  list(
    htmlDependency(
      name = "bootstrap-datepicker-js",
      version = datePickerVersion,
      src = c(href = "shared/datepicker"),
      script = "js/bootstrap-datepicker.min.js",
      # Need to enable noConflict mode. See #1346.
      head = "<script>(function() {
        var datepicker = $.fn.datepicker.noConflict();
        $.fn.bsDatepicker = datepicker;
      })();
     </script>"
    ),
    bootstraplib::bs_dependency_defer(datePickerCSS)
  )
}

datePickerCSS <- function(theme) {
  if (!is_bs_theme(theme)) {
    return(htmlDependency(
      name = "bootstrap-datepicker-css",
      version = datePickerVersion,
      src = c(href = "shared/datepicker"),
      stylesheet = "css/bootstrap-datepicker3.min.css"
    ))
  }

  scss_file <- system.file(package = "shiny", "www/shared/datepicker/scss/build3.scss")

  bootstraplib::bs_dependency(
    input = sass::sass_file(scss_file),
    theme = theme,
    name = "bootstrap-datepicker",
    version = datePickerVersion,
    cache_key_extra = utils::packageVersion("shiny")
  )
}
